<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    
</body>
<script>
    function connect({host = '127.0.0.1',username,password,port}){
        console.log(host);
        console.log(username);
    }
    const obj = {
        host:127.0,
        username:'李四',
        password:'1234',
        port:888
    }
    console.log(obj);
</script>
</html>